The difference between a legal hit and an illegal one in football is often determined by inches and seconds.
A proposed rule change by the NCAA could make those inches and seconds even more important in college football.
A player who delivers a hit to the head of a defenseless opponent could be kicked out of the game next season under an NCAA proposal that took a step forward Wednesday.
Consider this another high-profile step in the universal effort to make football less dangerous and cut down the risk of head injuries. The future of football became a hot topic again in the lead up to the Super Bowl when President Barack Obama said if he had a son ''he'd think long and hard'' before letting him play the game. He also voiced concern about whether the NCAA was doing enough to help college players deal with long-term health issues that come from playing football.
The NFL has been cracking down on helmet hits in recent seasons, handing out more frequent fines and even suspensions. But those penalties are determined days later, after the play has been reviewed.
Under the NCAA Football Rules Committee proposal, video replay will be used to determine the ejection part of the penalty, but that call will be made immediately.
And that's troubling to some coaches.
New Temple coach Matt Rhule, who spent the past last year as an assistant with the New York Giants, said it might be asking too much of replay officials to conduct a thorough review of a complex play that could result in a player losing the right to participate.
''That seems a high price to pay for something that we're not sure of,'' Rhule said in a telephone interview Wednesday night.
The rules committee said it had unanimously approved strengthening of the penalty for intentional above-the-shoulder hits. The 15-yard penalty will now have an ejection tacked on, assuming the Playing Rules Oversight Panel approves the plan next month.
''Clearly if the guy's head is down and he's launching into a receiver with the top of his head, that should be a penalty,'' Arizona coach Rich Rodriguez said. ''You hate for somebody to get penalized for just a good hard hit.''
Player safety was the theme of the committee's three-day meeting in Indianapolis, with the ejection for targeting the most noticeable change fans will notice in 2013 across all NCAA divisions. The committee also tweaked the rule on below-the-waist blocks.
Chairman and Air Force coach Troy Calhoun said the committee wanted to address clear instances where a defender is leading with the crown of his head to hit a defenseless player above the shoulders.
''It's a real problem in the sport,'' he said, ''and we need to eliminate it.''
Last season, Calhoun said, there were 99 targeting penalties called in the Football Bowl Subdivision that, under the proposed rule, would have called for an ejection. He said the player on the receiving end of the hit in many cases sustained a concussion or other type of injury that caused him to miss significant playing time.
''It's not a gigantic number,'' Calhoun said of the 99. ''Ultimately, our goal is zero. Is that realistic? I don't know if zero is. But I know any time you involve an ejection, we're going to see that number go down drastically immediately.''
If the penalty occurs in the first half, the player would be ejected for the remainder of the game. If the penalty occurs in the second half or overtime, the player is ejected for the remainder of the game and the first half of the next game.
The rule would allow for the ejection portion of the penalty to be reviewed through video replay. The replay official must have conclusive evidence that the penalized player didn't intentionally target a defenseless player in order to overturn the call on the field. Calhoun said the 15-yard portion of the penalty would not be reviewable.
Rhule was a college assistant from 1998-2011 before spending 2012 working for Tom Coughlin with the Giants. He returned to Temple, where he worked under Al Golden for five years, to lead the program in December.
He'd like to see college football take the NFL's approach. Throw a flag during the game, but when it comes to sitting a player down, let that decision be made later by an impartial panel, away from the pressures of a game.
The NFL also allows players to appeal suspensions and fine.
Ravens star safety Ed Reed was suspended for a game by the NFL this season for repeated hits to the head and neck area of defenseless players. On appeal, that was overturned.
''We should always err on the side of safety,'' he said. ''But what is the mechanism for after the fact, if a penalty happens in the first half, and a young man sits out and his team loses? Then they go back and look at it and they determine it wasn't an illegal hit. There was no intent to target the head. What are they then going to do?''
Rhule said suspending a player after a thorough review accomplishes the same thing as ejecting him, but removes the uncertainty that comes with a difficult call.
''I would love to see have the same punishment,'' Rhule said, ''but after the fact.''
AP Sports Writer Eric Olson contributed to this report.